What is they best album out there for showing off the sound quality of your system.

Pretty much any of the Steely Dan albums, my favorite is Countdown to Ecstasy.  Also, check out Alice Cooper, especially the first parts of these songs...Billion Dollar Babies, Ballad of Dwight Fry, Go to Hell.  The Who's "Eminence Front" and Kenny Wayne Shepard's "Blue on Black" are also excellent songs for showing off your system.  

If you have full range speakers that reproduce bass pretty well listen to Bela Fleck's "Flight of the Cosmic Hippo." Make sure you remove valuable items from your shelves .  

We been using 
Mfsl Supertramp crime of the century and Alan parsons I Robot 

@irish_tim : Your mention of Eminence Front reminded me that Pete Townshend's album White City is extremely well produced. The song "Hiding Out" is a great one for exercising your system.

Last night we listened to Donald Fagan The Nightfly.  Awesome!  I have so many albums that sound fantastic, it's hard to pick one.  Dire Straits - all of them - also come to mind.